Restaurants have grown irritatingly loud. What has that done to our taste?

DETROIT — Moments after the award-winning noodle shop Ima opened its doors for lunch on a recent Monday, a decibel meter perched high on a ledge above the dining room hovered around 70 decibels, about the same level of noise intensity as a working dishwasher.

Electronic music thrummed through two adjacent speakers, mixing with the low hum of kitchen equipment as the day’s first guests sauntered into the snug space for their fix of udon noodles in savory, umami-laden broth.

None of the guests paid any mind to the fluctuating red LED numbers near the ceiling, but the staff certainly did — by design.

“It kinda is rooted in the fact that our music and playlists were such an important part of our dining experience,” said Ima chef-owner Mike Ransom, who spent much of his early adult life moonlighting as a DJ. “And because we’re all music-minded, the levels are always something we’re very conscious of. And just like when you’re DJ-ing, the levels of music have to be adjusted and fine-tuned throughout the day or service.”

But, as Ransom found, one man’s loud is another’s library noise. Despite not being a totally accurate read thanks to its placement next to the speakers, Ima’s decibel meter was installed as a simple way to standardize the restaurant’s noise levels among the staff, who are instructed to keep the levels within a certain sweet spot, lower at lunch and higher during the busier dinner services to match the mood.

Unbeknownst to him, Ransom intuitively hit on a phenomenon a growing body of science is now beginning to help explain.

Anyone who eats out regularly has noticed restaurants grow significantly louder over the last two decades and it doesn’t take a scientist to understand why. Modern restaurant design trends favor open spaces and hard surfaces over their compartmentalized, acoustical ceiling-tiled, carpeted, linen-wrapped forebears.

And the loud rock ‘n’ roll or rap that was once reserved for the back-of-house prep staff’s boombox is now commonly piped into dining rooms — a trend often traced back to disgraced chef Mario Batali, who was known for blaring Led Zeppelin at the high-end Italian restaurant Babbo in New York in the ’90s. Thanks to a proliferation of open kitchens, there’s now often little separation between the kitchen and the dining room to begin with.

As restaurants have evolved, the noise inside them has become such a nuisance Americans named it the No. 1 most bothersome aspect of eating out, according to Zagat’s 2018 survey of dining trends, outweighing the usual suspects of bad service and high prices.

There’s now even an app for that, a self-styled “Yelp for restaurant noise” called SoundPrint, which allows diners to rate and submit noise levels at local restaurants using their smartphone’s internal microphone.

Over the last 10 years, other criticshave noted this clamorous phenomenon, some even incorporating noise levels into their reviews.

More recently, the Washington Post rightly pointed out the adverse effect that loud restaurants particularly have on people with hearing impairments, suggesting potential widespread violations of the Americans With Disabilities Act by the worst perpetrators.

All these issues are important and valid, but there’s been less media hand-wringing over how this new noisy normal may be impacting our perceptions of what we taste.

That, in fact, does take a scientist to explain.

THE TASTE OF SOUND

Charles Spence is the head of the Crossmodal Research Laboratory at Oxford University and is one of the leading psychologists synthesizing the research of how “the everything else” other than our taste buds affects our perceptions of taste.

“The pleasures of the table reside far more in the mind than we realize and perhaps even more in the mind than in the mouth,” Spence wrote last year in the journal Nutrition.

Spence is fascinated by the real-life applications of brain science and psychology, with a particular focus on how the senses interact. He has been studying “the everything else” in the dining experience for the past 15 years or so, beginning with an experiment that found people perceived Pringles to be crunchier and fresher when the researchers artificially boosted the sound of biting into the chip.

And thus, Spence began his journey into the world he calls “gastrophysics,” which marries gastronomy with psychophysics, publishing a book by the same name in 2017.

During a recent phone conversation, Spence called dining “perhaps one of the most multisensory of the experiences we have,” noting that the taste buds alone only provide a fraction of the experience we think of as taste.

“The taste buds are actually one of the least interesting bits of our taste experience,” he said. “Because if I blindfolded you, plugged your ears, blocked your nose with a swimming clip or something, then all you’d get in your mouth would just be sweet, bitter, salty, sour, umami. That’s it. And that’d be no kind of taste experience. Nothing that you’d like or crave or be interested in.”

Gastrophysics incorporates all the senses, and Spence says smell is one of the most important. But research in this field has also shown that everything from plate color to the weight of the cutlery to the the color of the walls to the tone and tempo of the background music all affect what we taste.

Still, it’s a noise-related anecdote that Spence says resonates most with strangers at dinner parties, probably because so many of us order tomato juice on airplanes without giving it much thought.

“I’ve been doing a fair amount of flying for work and sort of just observed this,” Spence said. “Seeing how many tomato juices were being ordered, we made a kind of a prediction in 2014 that we published with a chef and a philosopher saying, ‘There’s something funny going on here and the sound is the reason or a major part of the reason why people order the tomato juice.’’

The hypothesis was confirmed the following year by a pair of researchers at Cornell, who found that just playing the sound of cabin airplane noises suppressed sweetness while enhancing the flavor of umami, Spence said, “that sort of mysterious fifth taste that we find in tomatoes and bloody Marys and Worcestershire sauce.”

It’s an interesting phenomenon that certainly has implications for the noisy restaurant world, but Spence is careful to say that explanations for why it occurs should be taken with a healthy dose of skepticism at this point. They are merely hypotheticals.

“The simplest idea might be that any sort of loud noise or too much stimulation kind of masks our ability to taste, where one sense blacks out the others,” Spence said, noting that it’s probably not what’s going on in this case because of the heightening of umami.

“A second explanation might be that we have a separate line of research on sonic seasoning,” he said. “So actually selecting or composing picking music or soundscapes that have certain properties — pitch or tempo or roughness or loudness or timbre — in order to accentuate something in the tasting experience. So we have sweet music, we have sour music, we have bitter music.

“Who knows — we know that bitter music, for example, is low in pitch. So could it be that if we were to find the perfect sound for umami it might be similar to the spectrum of engine noise?”

The findings have potential ripple effects up and down the dining food chain, perhaps nowhere more obviously than at the upper echelon, where the world’s best chefs go to extreme lengths to serve diners a once-in-a-lifetime experience. In the hands of these chefs, Spence says a multisensory approach can create what he calls “extraordinary experiences.”

THUMPING MUSIC FUELS LUNCH RUSH

Chef Heston Blumenthal of the three-Michelin-starred Fat Duck restaurant in Bray, England, became fascinated with Spence’s work and turned into a willing participant in his “sonic chip” experiment.

Blumenthal famously turned this fascination into one of the Fat Duck’s signature dishes. Called “Sound of the Sea,” the dish features an arrangement of sashimi and tapioca “sand,” paired with a conch shell hiding an iPod that plays a specially composed track of sea sounds.

“How many of the journalists and people say, ‘I cried,’ (from the dish)?” Spence said. “It’s funny because I cried, too. It just took me back to being a child. And in a few other occasions from these experiential wine tastings where the music is designed to match the wine, people cry, grown adults, in a way that they wouldn’t cry to wine or seafood by itself or music by itself. Put them together and something special happens.”

These experiences may be extraordinary, but, on the level, they affect a very small percentage of restaurant diners who can afford to drop hundreds of dollars on a meal and very often plan cross-continental trips organized around one.

But everyday diners, like Sally Lindroth of Novi, are more likely to experience the negative side of noise in restaurants.

“My friends and I often have lunch or dinner out, and we increasingly find that we are unable to carry on conversation in a normal tone of voice,” Lindroth wrote in an email. “So many places with so much noise! It seems we always end up shouting at each other in order to make ourselves heard. We’ve tried going to places as early as possible, and that helps at the beginning, but as soon as a place begins to fill up, there we are again shouting across the table.”

The deployment of this science often eludes independent restaurants, but larger chains use it more subtly in the casual dining realm.

“On the one hand, it’s the top chefs who may draw these things out and highlight them to the diner: This is the way in which we can change taste and give you a thrilling experience,” Spence said. “In the mainstream maybe it’s happening off the radar. We’re being influenced by the same factors — the loudness, the tempo of the music is affecting how long we stay, how much we drink.”

Separate studies have shown that fast music and loud music make people drink alcohol faster, but that playing slow music led people to linger longer at dinner and spend more on drinks. This knowledge allows savvy restaurateurs to play their dining rooms almost like composers, speeding up the tempo during the busy rushes to turn tables and slowing it down when empty seats are ample. Many, like Ima’s Ransom, already do this on an intuitive level.

But it’s the big chains, Spence said, that are in a better position to use this knowledge and incorporate it.

In his book, Spence points to Chipotle, which very intentionally plays music with faster tempos during the lunch and dinner rushes to get people in and out quickly. And there’s the Hard Rock Cafe, which famously played loud, fast music because its founders realized it made people eat and drink more and get the hell out quickly.

“Of course, we won’t tell you that’s what we’re doing,” Spence said of the big chains who deploy this body of research to their benefit. “As a consumer, we’d rather you just focus on the food and how much you enjoy the experience.”

Pushed to the extremes, though, this sort of sonic flavoring can have the opposite effect, turning people away instead.

“There’s also a threshold,” Ransom said. “That’s where the decibel meter comes in. You want it to be something people are experiencing but not noticing to the point where it interrupts their meal.”

SOUND DATA

According to the Centers for Disease Control and Prevention, extended exposure to noise levels above 85 db, where many restaurants now typically hover, can lead to hearing loss.

Here are some everyday sounds and their typical noise intensity:

0 db: the softest sound that can be heard

10 db: normal breathing

20 db: a ticking watch

30 db: a soft whisper

60 db: normal conversation, an air-conditioner

70 db: a dishwasher or washing machine

80-85 db: gas-powered lawnmower or leaf blower

95 db: a motorcycle

100 db: approaching subway train

110 db: shouting or barking in the ear

120 db: standing near sirens

140-150 db: firecrackers

(Note that every 10 db increase represents a corresponding doubling of noise levels. If you need to shout to communicate to someone an arm’s length away, the level in the room is likely above 85 db.)